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Jan
17
revised Unable to understand hash function representations
polish
Jan
17
revised Unable to understand hash function representations
polish
Jan
17
reviewed Approve Unable to understand hash function representations
Jan
17
comment Proof that this is not a secure pseudorandom function
What you have tried does not work because $y_1=y_2$ does not hold in general when $x_2=y_1+p$ (further, adding $p$ is identity in $Z_p$ ). $\;$ You want to build a distinguisher for $F_k$. Arguably, $F_k(1)=1$ is enough for that, but you can build a more general distinguisher from $F_k(x_1\cdot x_2\bmod p)=F_k(x_1)\cdot F_k(x_2)\bmod p$.
Jan
16
comment Proof that this is not a secure pseudorandom function
Hint: multiplicative property
Jan
15
revised Can somebody help me understand RC4 Spritz? (Three Questions)
Give an element towards the third point
Jan
15
answered Can somebody help me understand RC4 Spritz? (Three Questions)
Jan
15
revised Defining Symmetric vs Asymmetric cryptosystems
links
Jan
15
revised Defining Symmetric vs Asymmetric cryptosystems
Polish
Jan
15
answered Defining Symmetric vs Asymmetric cryptosystems
Jan
14
comment Public key exponent coprime with totient proof
@fkraiem: you are right, the question as it stands now (and at the time I made my comment) asks a proof of:$$\gcd(e,\varphi(N))=1\implies\forall(x,y)\in\mathbb N^2,\;\big(x^e\equiv y^e\pmod N\implies\;x\equiv y\pmod N\big)$$ On the other hand, that was not originally clear, and I then got positive confirmation from the author that the question asks a proofs of:$$\gcd(e,\varphi(N))\ne1\implies\exists(x,y)\in\mathbb N^2,\;\;x\not\equiv y\pmod N,\;\;x^e\equiv y^e\pmod N$$Both are true, the first is well known, the second is less common.
Jan
13
awarded  signature
Jan
12
comment Simplied DES why 10-bit key?
Some data: William Stalling's Simplified DES has 8-bit plaintext and 10-bit key. The overview of appendix G of his Supplement to Cryptography and Network Security (Fifth Edition) states: "The algorithm could have been designed to work with a 16-bit key, consisting of two 8-bit subkeys, one used for each occurrence of $f_K$. Alternatively, a single 8-bit key could have been used, with the same key used twice in the algorithm. A compromise is to use a 10-bit key from which two 8-bit subkeys are generated...".
Jan
12
revised Is finding collisions in a part-hash not often enough a bad problem?
discuss mode, add picture
Jan
12
revised Is finding collisions in a part-hash not often enough a bad problem?
Give numerical multiplier
Jan
12
comment Can I shorten the large ECDSA public key output file from OpenSSL?
Yes. This gives constant size because the encoding uses BIT STRING rather than INTEGER.
Jan
12
revised What is the advantage of digital signatures over message authentication codes?
Re-polish
Jan
12
revised Lattice based attack on RSA
Link to updated paper
Jan
12
revised Is finding collisions in a part-hash not often enough a bad problem?
Polish
Jan
12
revised Is finding collisions in a part-hash not often enough a bad problem?
Emphasize the bound often used in crypto